提升熔石英透过率的表面随机结构研究

The output power, service life and reliability of laser are seriously limited by the low laser damage resistance of anti-reflection film. As the ability of improving transmittance of optical element and the laser damage resistance, the surface disorder structures (SDS) has attracted widely attention and research. In this research, we concentrate on model characterization and reconstruction, the electromagnetic field analysis, parameters optimization, fabrication technology improvement, optical performance analysis and the model correction. Firstly, the randomness of SDS is divided into two parts: individual features and the overall distribution state. Then we use finite-difference time-domain method (FDTD) and genetic algorithm (GA) to calculate the electromagnetic field and build the optimization method of structure parameters. Secondly, we want to design the parameters of SDS to improve the transmittance for wavelength of 355nm. Studying the metal particles mask preparation and reactive ion beam etching technology to develop a preparation process of SDS. Finally, we characterize the parameters of SDS which we fabricated, and measure the spectra. We will modify the model again by comparing the difference among the design spectra, the measured spectra and the spectra from inversion calculation. From this research, the transmittance of fused silica can be significantly improved and build a comprehensive study system for SDS.

减反射膜较低的抗激光损伤能力严重限制了激光器的输出功率、使用寿命及可靠性。表面随机结构（SDS，Surface Disorder Structures）作为提高光学元件的透过率和抗激光损伤能力的有效手段，引起了人们的广泛关注和研究。本项目涵盖SDS的表征与重构模型、电磁场分析与优化设计、制备工艺、光学性能分析与模型修正等研究内容。具体工作如下：将SDS的随机性分为个体形貌的随机性和整体分布的随机性进行表征重构，并基于时域有限差分法和遗传算法建立对SDS进行电磁场计算和光学性能优化的分析方法;基于上述方法，设计出对355nm的入射光具有高透过率的SDS参数；对金属颗粒掩膜制备和反应离子束刻蚀技术进行研究，探索得到相应的SDS制备工艺;对制备的SDS进行结构表征和光谱测量，通过对比设计光谱、实测光谱和反演光谱之间的差异对模型进行修正。基于上述研构建SDS从理论建模到性能分析的完整研究体系。

减反射膜较低的抗激光损伤能力严重限制了激光器的输出功率、使用寿命及可靠性。表面随机结构（SDS，Surface Disorder Structures）作为提高光学元件的透过率和抗激光损伤能力的有效手段，引起了人们的广泛关注和研究。.项目完成了表面随机减反结构的个体特征和整体分布的特征描述方法，重构了表面随机减反结构的理论计算形态模型，采用PSD谱线描述模型建立的有效性。并完成表面随机减反结构空间电磁场分布计算和优化算法的编译工作。设计得到了对波长355nm光有高透过率、大容差的参数，得到了随机结构的横向尺寸、纵向尺寸对光学性能的影响。.基于设计结果，不断优化工艺参数，得到磁控溅射技术镀制了20nm的银膜，再采用200℃的恒温20分钟得到了百纳米左右的银颗粒，基于反应离子束刻蚀技术将结构转移的熔石英基底上，将表面残留清洗后得到随机表面减反结构的熔石英窗口。测试得到随机减反结构的剩余反射在0.35%~0.55%之间，并且测量了随机结构的形貌，完成对理论模型的修正。.项目执行过程中共发表学术论文18篇，其中SCI收录16篇，国内外核心期刊2篇，申请发明专利5项，授权2项。